1. Field of the Invention
The present invention relates generally to an air conditioning system in a vehicle and, more particularly, to a method of air conditioning system temperature control for a motor vehicle.
2. Description of the Related Art
An air conditioning system is one feature on a motor vehicle to maintain the temperature of the occupant compartment of the motor vehicle at a comfortable level. The air conditioning system provides cool, dehumidified air for circulation in the occupant compartment of the motor vehicle. The primary components of the air conditioning system include a compressor, a refrigerant, air, an evaporator, a condenser, and a ventilation system. It is well known in the art for the air conditioning system to draw air to be cooled from outside the motor vehicle, from inside the occupant compartment of the motor vehicle, or from a mixture of outside and inside air.
From a vehicle occupant perspective, it is desirable to maintain the occupant compartment temperature at a comfortable level. The ability of the air conditioning system to maintain a consistent temperature may be affected by several factors such as a cab forward vehicle design. In a cab forward vehicle design, the frontal area of the grill is less than a conventional vehicle design, effectively reducing the potential volume of air available to the condenser of the air conditioning system.
Another factor is weather and driving conditions. For example, if the outside air temperature is elevated and the motor vehicle is stopped, or in city traffic, and the air conditioning system is in an outside air mode, the air conditioning system must work harder to remove heat from the air. This can lead to a higher air conditioning compressor discharge pressure, and a higher pressure may lead to a higher air conditioning system outlet air temperature. Also, with an increased air conditioning compressor discharge pressure, there is a potential for the performance of the air conditioning compressor to be degraded. Furthermore, the durability of an individual air conditioning system component may be compromised by an increased air conditioning compressor discharge pressure. Thus, there is a need in the art for a method of controlling an air conditioning compressor discharge pressure for improving temperature control within the occupant compartment of the motor vehicle.